Introduction

The aim of this project is the development and construction of an interface between a CMOS camera and a computer. This interface allows a user to get images from the camera, to change some of the properties of the camera as brightness, luminance, etc from a computer. Also some image process is implemented allowing the camera to track white objects and follow them with a servomotor. The interface was implemented using the Atmel AVR ATmega16 micro controller.

The System

The communication from the microcontroller to the camera to change the properties of the camera is made using the I2C. The images from the camera are read following the Zoom Video Port Format implemented by the camera. The images read are in black and white because only the Y channel is read. To control all this communications the microcontroller is connected to the computer via serial port. The microcontroller read commands from the computer and perform the appropriate actions. The serial port is also used to receive the images in BMP format

Some image process is made to detect the center of a white object. The microcontroller can use this information to track white objects with a servo motor. The servomotor is also used to get panoramic images by changing the position of the camera while taking the photo

for report and presentation see
http://robozesinaki/dproject/

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Digital Camera
Introduction to a simple digital camera
• Captures images
• Stores images in digital format
– No film
– Multiple images stored in camera
• Number depends on amount of memory and bits used per image
• Downloads images to PC
• Only recently possible
– Systems-on-a-chip
• Multiple processors and memories on one IC
– High-capacity flash memory
• Very simple description used for example
– Many more features with real digital camera
• Variable size images, image deletion, digital stretching, zooming in and out, etc.
Designer’s perspective
• Two key tasks
– Processing images and storing in memory
• When shutter pressed:
– Image captured
– Converted to digital form by charge-coupled device (CCD)
– Compressed and archived in internal memory
– Uploading images to PC
• Digital camera attached to PC
• Special software commands camera to transmit archived images serially
Charge-coupled device (CCD)
• Special sensor that captures an image
• Light-sensitive silicon solid-state device composed of many cells
When exposed to light, each cell becomes electrically charged. This charge can then be converted to a 8-bit value where 0 represents no exposure while 255 represents very intense exposure of that cell to light.
Some of the columns are covered with a black strip of paint. The light-intensity of these pixels is used for zero-bias adjustments of all the cells.
The electromechanical shutter is activated to expose the cells to light for a brief moment.
The electronic circuitry, when commanded, discharges the cells, activates the electromechanical shutter, and then reads the 8-bit charge value of each cell. These values can be clocked out of the CCD by external logic through a standard parallel bus interface